Árdegis - Síðdegis

Árdegis og Síðdegis are the earliest instructional marks used in Iceland, and solely used in Reykjavík. An account, dated 11 April 1901 for the making, amounts 4.40 krónur. Nothing has been found so far that implies how to use these marks, but it's obvious that Árdegis means that the item was posted too late for Morning Delivery and Síðdegis means "too late for Afternoon Delivery". In spite of the huge amount of cards posted after 1900 announcing meetings of all kind, it's strange how few cards are known with these marks. Please add to the list below if/when possible.
Árdegis	Baron H. von Jaden	bréf/letter		25.7.1902
Árdegis	Herra kand.phil. Einar Gunnarsson	(bréf)		1.10.1902
Árdegis	Eiríkur Briem			24.11.1902
Árdegis	Jón Jensson	yfirdómari		24.11.1902
Árdegis	Jón Magnússon	landritari		24.11.1902
Árdegis	Axel Jósefsson		Laugaveg 24	21.12.1902
Árdegis	Guðmundur Pétursson	stud med.		4.2.1903
Árdegis	Guðmundur Pétursson	stud med.		11.2.1903
Árdegis	Eiríkur Briem			23.2.1903
Árdegis	Eiríkur Sverrisson	hr. cand.phil.		10.11.1903
Árdegis	Guðmundur Pétursson	stud med.		10.11.1903
Árdegis	Eiríkur Sverrisson	Cand. phil.		11.12.1903
Árdegis	Lárus Thorarensen			11.12.1903
Árdegis	Henrik Erlendsson	stud.med.		15.12.1903
Árdegis	Lárus Thorarensen			15.12.1903
Árdegis	Vilh. Bernhöft	tand.		15.12.1903
Árdegis	Lárus Thorarensen	stud theol.		17.12.1903
Árdegis	Vilh. Bernhöft	læknir		17.12.1903
Árdegis	Vantar uppl.			5.2.1904
Árdegis	Jón Kristjánsson	stud med.	Skólavörðustíg 11 A	7.3.1905
Árdegis	Jón Þorkelsson	Hr. Dr. phil.		3.7.1905
Árdegis	Pétur Zóphóníasson			19.12.190?
In all: 22 Árdegis-cancellations registered
Síðdegis	Til Landfógetans	(þjónustubréf)	Rvík	19.11.1901
Síðdegis	Hinrik Erlendsson	(póstkort)	Þingholtsstræti 5	24.12.1901
Síðdegis	Til herra landfógeta A. Thorsteinsson	(bréf)	Austurstræti 20	22.1.1902
Síðdegis	Pálmi Pálsson	adjunct	(bréf / The Chess Cover)	21.6.1902
Síðdegis	Eiríkur Briem			30.10.1902
Síðdegis	Bogi Brynjólfsson			20.12.1902
Síðdegis	Sigurbjörn Á. Gíslason		Þingholtsstræti 3	20.1.1903
Síðdegis	Jón Magnússon	landritari	Þingholtsstræti	23.2.1903
Síðdegis	Jón Pálsson	verzlunarmaður	Laugaveg 41	13.3.1903
Síðdegis	M. Lund	Apoteker		13.3.1903
Síðdegis	Jens B. Waage	Cand.		30.3.1903
Síðdegis	Jens B. Waage	Cand.		30.6.1903
Síðdegis	E. Sverrisson	skrifari		7.12.1903
Síðdegis	Lárus Thorarensen	stud theol		7.12.1903
Síðdegis	Guðmundur Pétursson			23.2.1904
Síðdegis	Jón Jensson	assessor	Þingholtsstræti	26.5.1904
Síðdegis	Jón Þorkelsson (bréf)	landskjalavörður		22.2.1905
Síðdegis	??		Skrifað á Eyrarbakka	??.??.????
In all: 18 Síðdegis-cancellations registered